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<title>OPENSSL_secure_malloc</title>
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<ul id="index">
  <li><a href="#NAME">NAME</a></li>
  <li><a href="#SYNOPSIS">SYNOPSIS</a></li>
  <li><a href="#DESCRIPTION">DESCRIPTION</a></li>
  <li><a href="#RETURN-VALUES">RETURN VALUES</a></li>
  <li><a href="#SEE-ALSO">SEE ALSO</a></li>
  <li><a href="#HISTORY">HISTORY</a></li>
  <li><a href="#COPYRIGHT">COPYRIGHT</a></li>
</ul>

<h1 id="NAME">NAME</h1>

<p>CRYPTO_secure_malloc_init, CRYPTO_secure_malloc_initialized, CRYPTO_secure_malloc_done, OPENSSL_secure_malloc, CRYPTO_secure_malloc, OPENSSL_secure_zalloc, CRYPTO_secure_zalloc, OPENSSL_secure_free, CRYPTO_secure_free, OPENSSL_secure_clear_free, CRYPTO_secure_clear_free, OPENSSL_secure_actual_size, CRYPTO_secure_allocated, CRYPTO_secure_used - secure heap storage</p>

<h1 id="SYNOPSIS">SYNOPSIS</h1>

<pre><code>#include &lt;openssl/crypto.h&gt;

int CRYPTO_secure_malloc_init(size_t size, int minsize);

int CRYPTO_secure_malloc_initialized();

int CRYPTO_secure_malloc_done();

void *OPENSSL_secure_malloc(size_t num);
void *CRYPTO_secure_malloc(size_t num, const char *file, int line);

void *OPENSSL_secure_zalloc(size_t num);
void *CRYPTO_secure_zalloc(size_t num, const char *file, int line);

void OPENSSL_secure_free(void* ptr);
void CRYPTO_secure_free(void *ptr, const char *, int);

void OPENSSL_secure_clear_free(void* ptr, size_t num);
void CRYPTO_secure_clear_free(void *ptr, size_t num, const char *, int);

size_t OPENSSL_secure_actual_size(const void *ptr);

int CRYPTO_secure_allocated(const void *ptr);
size_t CRYPTO_secure_used();</code></pre>

<h1 id="DESCRIPTION">DESCRIPTION</h1>

<p>In order to help protect applications (particularly long-running servers) from pointer overruns or underruns that could return arbitrary data from the program&#39;s dynamic memory area, where keys and other sensitive information might be stored, OpenSSL supports the concept of a &quot;secure heap.&quot; The level and type of security guarantees depend on the operating system. It is a good idea to review the code and see if it addresses your threat model and concerns.</p>

<p>If a secure heap is used, then private key <b>BIGNUM</b> values are stored there. This protects long-term storage of private keys, but will not necessarily put all intermediate values and computations there.</p>

<p>CRYPTO_secure_malloc_init() creates the secure heap, with the specified <code>size</code> in bytes. The <code>minsize</code> parameter is the minimum size to allocate from the heap. Both <code>size</code> and <code>minsize</code> must be a power of two.</p>

<p>CRYPTO_secure_malloc_initialized() indicates whether or not the secure heap as been initialized and is available.</p>

<p>CRYPTO_secure_malloc_done() releases the heap and makes the memory unavailable to the process if all secure memory has been freed. It can take noticeably long to complete.</p>

<p>OPENSSL_secure_malloc() allocates <code>num</code> bytes from the heap. If CRYPTO_secure_malloc_init() is not called, this is equivalent to calling OPENSSL_malloc(). It is a macro that expands to CRYPTO_secure_malloc() and adds the <code>__FILE__</code> and <code>__LINE__</code> parameters.</p>

<p>OPENSSL_secure_zalloc() and CRYPTO_secure_zalloc() are like OPENSSL_secure_malloc() and CRYPTO_secure_malloc(), respectively, except that they call memset() to zero the memory before returning.</p>

<p>OPENSSL_secure_free() releases the memory at <code>ptr</code> back to the heap. It must be called with a value previously obtained from OPENSSL_secure_malloc(). If CRYPTO_secure_malloc_init() is not called, this is equivalent to calling OPENSSL_free(). It exists for consistency with OPENSSL_secure_malloc() , and is a macro that expands to CRYPTO_secure_free() and adds the <code>__FILE__</code> and <code>__LINE__</code> parameters..</p>

<p>OPENSSL_secure_clear_free() is similar to OPENSSL_secure_free() except that it has an additional <code>num</code> parameter which is used to clear the memory if it was not allocated from the secure heap. If CRYPTO_secure_malloc_init() is not called, this is equivalent to calling OPENSSL_clear_free().</p>

<p>OPENSSL_secure_actual_size() tells the actual size allocated to the pointer; implementations may allocate more space than initially requested, in order to &quot;round up&quot; and reduce secure heap fragmentation.</p>

<p>OPENSSL_secure_allocated() tells if a pointer is allocated in the secure heap.</p>

<p>CRYPTO_secure_used() returns the number of bytes allocated in the secure heap.</p>

<h1 id="RETURN-VALUES">RETURN VALUES</h1>

<p>CRYPTO_secure_malloc_init() returns 0 on failure, 1 if successful, and 2 if successful but the heap could not be protected by memory mapping.</p>

<p>CRYPTO_secure_malloc_initialized() returns 1 if the secure heap is available (that is, if CRYPTO_secure_malloc_init() has been called, but CRYPTO_secure_malloc_done() has not been called or failed) or 0 if not.</p>

<p>OPENSSL_secure_malloc() and OPENSSL_secure_zalloc() return a pointer into the secure heap of the requested size, or <code>NULL</code> if memory could not be allocated.</p>

<p>CRYPTO_secure_allocated() returns 1 if the pointer is in the secure heap, or 0 if not.</p>

<p>CRYPTO_secure_malloc_done() returns 1 if the secure memory area is released, or 0 if not.</p>

<p>OPENSSL_secure_free() and OPENSSL_secure_clear_free() return no values.</p>

<h1 id="SEE-ALSO">SEE ALSO</h1>

<p><a href="../man3/OPENSSL_malloc.html">OPENSSL_malloc(3)</a>, <a href="../man3/BN_new.html">BN_new(3)</a></p>

<h1 id="HISTORY">HISTORY</h1>

<p>The OPENSSL_secure_clear_free() function was added in OpenSSL 1.1.0g.</p>

<h1 id="COPYRIGHT">COPYRIGHT</h1>

<p>Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.</p>

<p>Licensed under the OpenSSL license (the &quot;License&quot;). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p>


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